<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>真假测试</title>
</head>

<body>
    <script type="text/javascript">
    function booWho(bool) {
        // What is the new fad diet for ghost developers? The Boolean.
        return bool;
    }

    booWho(null);
    </script>
</body>

</html>